Apparatus and Method for Measuring Inclination in Subsea Running, Setting, and Testing Tools

ABSTRACT

A system for jetting a borehole in a seafloor, the system including a tubular, and a jetting tool inserted into the tubular and having an end from which fluid is selectively discharged to excavate the borehole. An electrical inclination sensor is attached to the stem of the tubular, and is in communication a transmitter. A receiver is positioned proximate the sea surface and is in communication with the transmitter through the fluid in a drill pipe, so that when the jetting tool is excavating the borehole, an inclination of the tubular is sensed by the inclination sensor, which inclination is communicated from the transmitter to the receiver.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This technology relates to subsea oil and gas wells. In particular, thistechnology relates to measurement of inclination of running, setting,and testing tools during the primary phase of jetting a subsea well.

2. Brief Description of Related Art

Typical subsea drilling operations include a drilling vessel and anarrangement of equipment to accomplish the first drilling phase of awell. Where the sea floor is sandy, the first phase of the drillingoperation may include jetting. Jetting is a process wherein a jettingtool, enclosed within a casing, is placed adjacent the sea floor. Fluidis sprayed through the end of the jetting tool and directed at the sandon the sea floor. The fluid is turbulent and stirs up the sand, whichmixes with the fluid and is carried up the casing away from the bottomof the casing. When the sand is thus removed, the casing is lowered intothe void left behind. This process is continued until the casing reachesa predetermined depth, after which equipment related to the next phaseof drilling (i.e. a high pressure housing, blow out preventer, marineriser, etc.) is connected.

It is beneficial for the equipment used in this first stage of drillingto be vertically oriented while the well is created. Such a verticalorientation allows for straight and proper connections of equipment usedin subsequent phases of drilling. Accordingly, monitoring theinclination of the jetting equipment used during the first phase ofdrilling may be beneficial to help ensure that a vertical orientation ismaintained.

SUMMARY OF THE INVENTION

Disclosed herein is a system for jetting a borehole in a sea floor. Inan example, the system includes a tubular having a stem, a housingrunning and jet tool, and a jetting tool inserted into the tubular andhaving an end from which fluid is selectively discharged to excavate theborehole. An electrical inclination sensor is attached either to thestem of the tubular, or to the housing running and jet tool. Theelectrical inclination sensor measures vertical inclination of thejetting tool and the housing running and jet tool.

A transmitter is attached to the electrical inclination sensor thatreceives information related to the inclination of the jetting tool andthe housing running and jet tool from the electrical inclination sensor.The transmitter than transmits either a mud pulse signal or an acousticsignal, depending on the placement of the transmitter, containinginformation about the inclination of the jetting tool and the housingrunning and jet tool.

A receiver is located at the drilling vessel and is configured toreceive the mud pulse or other acoustic signal from the transmitter. Ifthe transmitter is attached to the stem of the jetting tool, thereceiver may be attached to a receptor at the top of the drill string.If the transmitter is attached to the housing and drill tool, so that istransmits acoustic signals into the sea water, the receiver may bepositioned near the drilling vessel and submerged in the sea.

Also disclosed herein is a method for jetting a borehole in a sea floor.The method includes the steps of jetting a borehole by selectivelydischarging fluid our of a jetting tool directed at the sea floor, andproviding an electrical inclination sensor that measures the inclinationof the jetting tool. The method also provides monitoring the inclinationof the jetting tool with the electrical inclination sensor prior to andduring drilling activities, acoustically transmitting a signalcontaining information about the inclination of the jetting tool via atransmitter attached to the electrical inclination sensor, and receivingthe signal with a receiver proximate the sea surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The present technology will be better understood on reading thefollowing detailed description of nonlimiting embodiments thereof, andon examining the accompanying drawings, in which:

FIG. 1A is a perspective view of a jetting assembly according to anembodiment of the present technology;

FIG. 1B is an enlarged view of the area indicated by the circle 1B inFIG. 1A;

FIG. 2 is a side view of the jetting assembly of claim 1 in operationduring a primary phase of drilling a well;

FIG. 3A is a perspective view of a system for running, setting, andtesting subsea jetting tools according to an embodiment of the presenttechnology;

FIG. 3B is an enlarged side view of a portion of the jetting equipmentshown in FIG. 3A, as indicated by the area 3B of FIG. 3A;

FIG. 4 is a side view of a the jetting assembly according to anembodiment of the present technology, with a known analog inclinationsensor and a remotely operated vehicle;

FIG. 5A is a side view of the jetting assembly according to anembodiment of the present technology, including an electricalinclination sensor attached to the stem of the housing running and jettool;

FIG. 5B is an enlarged side view of the electrical inclination toolattached to the stem of the housing running and jet tool, as indicatedby area 5B of FIG. 5A;

FIG. 6 is a perspective view of components of a system for running,setting, and testing subsea jetting tools according to an embodiment ofthe present technology, including a transmitter and receiver configuredto communicate via mud pulse data transmission;

FIG. 7A is a side view of components of a system for running, setting,and testing subsea jetting tools according to an embodiment of thepresent technology, including a transmitter and receiver configured tocommunicate via acoustic data transmission; and

FIG. 7B is a side view of a portion of the jetting assembly, includingan electrical inclination sensor and a transmitter configured foracoustic data transmission, as indicated by area 7B of FIG. 7A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The foregoing aspects, features, and advantages of the presenttechnology will be further appreciated when considered with reference tothe following description of preferred embodiments and accompanyingdrawings, wherein like reference numerals represent like elements. Indescribing the preferred embodiments of the technology illustrated inthe appended drawings, specific terminology will be used for the sake ofclarity. However, the technology is not intended to be limited to thespecific terms used, and it is to be understood that each specific termincludes equivalents that operate in a similar manner to accomplish asimilar purpose.

FIG. 1A shows a jetting assembly 10 according to an embodiment of thepresent technology, including a low pressure housing 12, a casing string14, a housing running and jet tool 16, drill pipe 18, and a jetting tool20. The housing running and jet tool 16 has a stem 21. Jetting assembly10 is configured to accomplish the first phase of a drilling program, bybeginning drilling a wellbore into the sea floor. As shown in FIG. 1B,when the jetting assembly 10 is assembled, the end 22 of the jettingtool 20 is positioned a predetermined distance D from the bottom of thecasing string 14. In one embodiment, this distance D may be about 18inches. Before initiating jetting operations, and during the course ofjetting the first phase of the well, it is desirable for the jettingassembly 10, and in particular the drill pipe 18 and the casing 14, tobe vertically oriented. Such a vertical orientation allows for thesuccessful connection and operation of equipment during subsequentdrilling phases.

FIG. 2 shows the jetting assembly 10 in practice. Once the jettingassembly 10 is positioned vertically adjacent the sea floor 24, thejetting tool 20 ejects fluid downward toward the sea floor 24. Theejection of fluid causes turbulence at the end of the casing string 14,which turbulence stirs up the sand and sediment on the sea floor 24. Asthe sand and sediment is stirred up, it is carried by the fluid upwardlythrough the casing string 14, along the path indicated by arrows A. Inthe embodiment shown, the sand and sediment may be discharged into thesea through the low pressure housing 12. As the sand and sediment isstirred and carried upward by the drill fluid, a void space is createdimmediately below the casing string 14. The casing string 14 thentravels downward to fill the void space. This sequence of operation(i.e., jetting, removal of sand and sediment, and lowering of the casingstring) is repeated as needed until the assembly 10 achieves apredetermined depth. The fluid may be incontaminable, to minimize oreliminate environmental hazards when the fluid is discharged in the seaalong with the sand and sediment.

Referring to FIG. 3A, there is shown a system for running, setting, andtesting subsea jetting tools, including equipment used to carry outsubsequent phases of drilling after the first phase is completed.Specifically, FIG. 3A shows a drilling vessel 26, located at the surfaceof the sea, and additional subsea drilling equipment located at the seabed 24. Although the drilling vessel 26 is shown to be a ship, it couldalso be a drilling platform, such as, for example, a floating platform,tension leg platform, etc. An enlarged view of some of this additionalsubsea drilling equipment is shown in FIG. 3B, and includes the lowpressure housing 12, a high pressure housing 30 configured for insertioninside the low pressure housing 12, and a pressure management device 32,such as, for example, a blowout preventer (BOP). As shown, the subseadrilling equipment may be connected to the drilling vessel 26 by amarine riser 28.

In practice, the jetting assembly 10 may be assembled on the drillingvessel 26. To accomplish this, the housing running and jet tool 16 isinserted and locked into the low pressure housing 12. Drill pipe 18 isalso attached to the housing running and jet tool 16. This may beaccomplished by connecting a bottom thread of the housing running andjet tool 16 to a top thread of the drill pipe 18. Similarly, the jettingtool 20 may then be attached to the drill pipe 18 by, for example,connecting a bottom thread of the drill pipe 18 with a top thread of thejetting tool 20. The casing string 14 is also connected to the lowpressure housing 12, and is configured so its bottom end is apredetermined distance D from the bottom end 22 of the jetting tool 20,as discussed above. Once the jetting assembly 10 has been assembled, itis lowered to the sea floor. The jetting assembly 10 remains connectedto the drilling vessel 26 by a drill pipe (not shown) which extendsupwardly through the marine riser 28 from the jetting assembly 10 to thedrilling vessel 26. The fluid to be ejected by the jetting tool 20 isdelivered to the jetting tool 20 from the drilling vessel 26 via thedrill pipe 18.

As discussed above, it is desirable that the jetting assembly 10maintain a vertical orientation through the jetting phase. Accordingly,FIG. 4 shows one known method of verifying such a vertical orientationthat includes an analog inclination measuring device 34 attached to thejetting assembly 10. In an example, an analog inclination measuringdevice 34 is of the type known as a “Bullseye” device in the industrythat includes liquid in a sealed chamber, and a ball floating in theliquid. Reference lines are drawn on surfaces of the chamber, and as theequipment inclines, the liquid pushes the floating ball to acorresponding reference line. Association of the ball with a particularreference line indicates how much the device is inclined. Options existwhere the analog inclination measuring device 34 is attached to orformed integrally with, the housing running and jet tool 16.

In practice, the use of such an analog inclination measuring device 34requires that an inclination reading be taken between each iteration ofjetting (i.e., between each sequence of jetting, sand and sedimentremoval, and lowering of the casing string). Such an inclination readingrequires use of a remotely operated vehicle (ROV) 36, and can be timeconsuming and inefficient. This is because the ROV 36 can only read theanalog inclination measuring device 34 from close proximity, as shown inFIG. 4. During the actual jetting operation, however, the ROV 36 must bepositioned relatively far away from the jetting assembly 10 so as not tointerfere with operations. This means that between each iteration ofjetting, the ROV 36 must move into close proximity of the analoginclination measuring device 34, take the inclination reading, transmitthe reading to an operator on the drilling vessel 26, and move back awayfrom the jetting assembly 10 a safe distance.

A better way to measure the inclination of the jetting assembly 10 isthrough the use of an electrical inclination sensor 38, as shown inFIGS. 5A and 5B. One example of such an electrical inclination sensor 38is disclosed in U.S. Pat. No. 4,937,518, which is hereby incorporated byreference herein. As shown, the electrical inclination sensor 38 isattached to the jetting assembly 10, and is configured to send aninclination signal to an operator on the drilling vessel 26 in realtime. In some embodiments, the electrical inclination sensor 38 may beattached to the stem 21 of the housing running and jet tool 16. In otherembodiments, the electrical inclination sensor 38 may be attached to thelow pressure housing 12 (as shown in FIG. 7).

The real time transmission of inclination data from the jetting assembly10 to an operator on the drilling vessel 26 is advantageous because iteliminates the need to stop jetting between each jetting iteration toallow the ROV 36 to take an inclination reading. Furthermore, the realtime transmission allows an operator to detect a problem with theinclination immediately when the problem occurs, rather than waiting forthe next break between jetting iterations. Thus, the jetting process ismore efficient, and potential problems can be identified and remediedmore rapidly.

Signal transmission from the electrical inclination sensor 38 to theoperator on the drilling vessel 26 can be accomplished in at least twodifferent ways. For example, the data signal from the electricalinclination sensor 38 can be sent via mud pulse transmission (shown inFIG. 6) or acoustic data transmission (shown in FIG. 7). In each case,the data signal is transmitted from the electrical inclination sensor 38by a transmitter 40, and received by a receiver 42.

In the case of mud pulse transmission, shown in FIG. 6, the electricalinclination sensor 38 may be attached to the stem 21 of the housingrunning and jet tool 16. The transmitter 40 may also be attached to thestem 21 of the housing running and jet tool 16, and may be connected tothe electrical inclination sensor 38 by a wire (not shown). Coupled withthe drill pipe 18, proximate the drilling vessel 26, is a receptor stem44. The receptor stem 44 may be attached to the drill pipe 18 byengaging a top thread of the drill pipe 18 with a corresponding bottomthread of the receptor stem 44. A receiver 42 is attached to thereceptor stem 44 and in communication with a display 46 that is viewableby an operator.

In practice, the electrical inclination sensor 38 determines theinclination of the stem 21 of the housing running and jet tool 16, whichcorresponds to the inclination of the entire drill assembly 10. Theinclination sensor 38 then communicates the inclination data to thetransmitter 40. Next, the transmitter 40 transmits an inclination datasignal upward in a pulse through the mud surrounding the stem 21 and thedrill pipe 18 to the receptor stem 44. At the receptor stem 44, thereceiver 42 receives the signal, and communicates the inclination datato the display 46. In certain embodiments, the inclination data isgenerated constantly by the electrical inclination sensor 38 andtransmitted in real time to the receiver 42. Thus, the operator receivescontinuous real time data about the inclination of the drill assembly 10throughout the primary jetting process.

In an example of acoustic data transmission, as shown in FIGS. 7A and7B, the electrical inclination sensor 38 is attached to an outer face ofthe low pressure housing member 12. Likewise, the transmitter 40 isattached to the outer surface of the low pressure housing member 12, andis connected to the electrical inclination sensor 38 by a wire (notshown). Receiver 42 is positioned near the drilling vessel 26 (shown asa floating platform in FIG. 7), and is connected to a display 46 (shownin FIG. 6) that is viewable by an operator.

In an example of operation, the electrical inclination sensor 38 sensesan inclination of the low pressure housing 12, which corresponds to theinclination of the entire drill assembly 10. The inclination sensor 38then communicates the inclination data to the transmitter 40, whichtransmits an inclination data signal into the surrounding sea water thatis received by receiver 42. Based on the received signal, the receiver42 communicates the inclination data to the display 46. In certainembodiments, the inclination data is generated constantly by theelectrical inclination sensor 38 and transmitted in real time to thereceiver 42. Thus, the operator receives continuous real time data aboutthe inclination of the drill assembly 10 throughout the primary jettingprocess. In this embodiment, the receiver 42 is submerged in the seawater proximate the vessel so that it can better intercept the acousticsignals transmitted by the transmitter 40.

In certain embodiments, the receiver 42 can communicate with an analysisdevice or system, such as a computer, processor, network, software,analytics engine, etc. Such communication may be by means of a wire, orwireless transmission signals. The analysis device or system may beadapted to react to certain data received from the receiver 42 by, forexample, sounding an alarm, sending a message, or sending controlsignals to automatically or semi-automatically control the equipment. Inaddition, the analysis device or system could be located near thereceiver 42 or remote from the receiver 42, such as, for example, at adistant location.

While the technology has been shown or described in only some of itsforms, it should be apparent to those skilled in the art that it is notso limited, but is susceptible to various changes without departing fromthe scope of the invention. Furthermore, it is to be understood that theabove disclosed embodiments are merely illustrative of the principlesand applications of the present invention. Accordingly, numerousmodifications may be made to the illustrative embodiments and otherarrangements may be devised without departing from the spirit and scopeof the present invention as defined by the appended claims.

What is claimed is:
 1. A system for jetting a borehole in a seafloor,the system comprising: a tubular; a jetting tool inserted into thetubular and having an end from which fluid is selectively discharged toexcavate the borehole; an electrical inclination sensor attached to thestem of the tubular; a transmitter in communication with the electricalinclination sensor; and a receiver proximate the sea surface and incommunication with the transmitter through the fluid in a drill pipe, sothat when the jetting tool is excavating the borehole, an inclination ofthe tubular is sensed by the inclination sensor, which inclination iscommunicated from the transmitter to the receiver.
 2. The system ofclaim 1, further comprising a display in communication with the receiverthat is accessible to an operator, and shows the information transmittedto the receiver.
 3. The system of claim 1, wherein the transmittertransmits, and the receiver receives, information about the inclinationof the tubular continuously in real time.
 4. The system of claim 1,wherein communication between the receiver and the transmitter comprisesacoustic pulses that propagate through the drill pipe.
 5. A system forjetting a borehole in a seafloor, the system comprising: running andsetting tools, including at least a housing running and jet tooloperatively connected to a drilling vessel, and a jetting tool having anend from which fluid is selectively discharged to excavate the borehole;an electrical inclination sensor attached to the housing running and jettool, and capable of measuring the relative vertical inclination of thehousing running and jet tool; a transmitter attached to the electricalinclination sensor that receives information related to the inclinationof the housing running and jet tool from the electrical inclinationsensor, and that transmits an acoustic signal containing informationabout the inclination of the housing running and jet tool into the sea;and a receiver located proximate the drilling vessel and at leastpartially submerged in the sea, the receiver configured to receive theacoustic signal from the transmitter.
 6. The system of claim 5, furthercomprising a display in communication with the receiver, and accessibleto an operator, that shows the information transmitted to the receiverin the acoustic signal.
 7. The system of claim 5, wherein thetransmitter transmits, and the receiver receives, information about theinclination of the housing running and jet tool continuously in realtime.
 8. A method for jetting a borehole in a seafloor, the methodcomprising: jetting a borehole by selectively discharging fluid out of ajetting tool directed at the sea floor; providing an electricalinclination sensor that measures the inclination of the jetting tool;monitoring the inclination of the jetting tool with the electricalinclination sensor prior to and during jetting activities; andacoustically transmitting, to a receiver proximate the sea surface, asignal containing information about the inclination of the jetting toolvia a transmitter attached to the electrical inclination sensor.
 9. Themethod of claim 8, further comprising the step of displaying theinformation about the inclination of the jetting tool on a displayscreen in communication with the receiver.
 10. The method of claim 8,wherein the step of monitoring the inclination of the jetting tool iscarried out continuously in real time during the landing and setting ofsubsea wellhead consumables on the sea floor.
 11. The method of claim 8,wherein the jetting tool is deployed on a fluid filled tubular string,and wherein the step of acoustically transmitting the signal comprisesdirecting pulses through the fluid in the string.
 12. The method ofclaim 8, wherein the step of acoustically transmitting the signalcomprises directing pulses through sea water.
 13. The method of claim 8,further comprising the step of receiving the signal by the receiver.